The present invention relates to moisture curable room temperature vulcanizable (RTV) organopolysiloxane compositions utilizing a mixture of a bis(ureido) silane coupler and an aminoxy silane crosslinker for a silanol-terminated polydiorganosiloxane base polymer.
Prior to the present invention as shown by Klosowski, U.S. Pat. No. 3,996,184, vulcanizable silicone elastomers were provided using a mixture of a bis(N-organoacetamido)silane and a tris(aminoxy)silane to convert a hydroxy endblocked polydimethylsiloxane to a silicone elastomer. The compositions of Klosowski also contain a solvent, such as N,N-dimethylformamide, as well as up to 200 parts of a non-reinforcing filler, per 100 parts by weight of the silanol-terminated polydiorganosiloxane. Additional room temperature vulcanizable organopolysiloxane compositions using a dual catalyst system are shown by Goossens U.S. Pat. No. 3,338,868, Clark et al. U.S. Pat. No. 3,766,127, and Toporcer et al. U.S. Pat. No. 3,817,909.
Although the aforementioned moisture curable room temperature vulcanizable organopolysiloxane compositions provide valuable silicone elastomers useful in various construction applications, an enhancement in the cure rate, improvement in ultimate elongation and reduction in the modulus of these elastomers are desirable. In addition, many of such applications cannot tolerate an organic solvent, such as N,N-dimethylformamide, or acetonitrile